Mounting system that maintains stability of optics as temperature changes

ABSTRACT

An optical system comprises a detector to determine one or more intensities of light impinging on one or more locations of the detector and an optical element to direct light towards the detector along a detection axis. The detector and optical element are coupled together by three or more substantially flat flexures respectively defining three or more flexure planes parallel to the detection axis. The three or more substantially flat flexures maintain an alignment of the optical element to the detector with changes in temperature.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/287,641, Filed Oct. 6, 2016, which is a continuationapplication of U.S. patent application Ser. No. 14/316,698, filed Jun.26, 2014, issued as U.S. Pat. No. 9,491,863 on Nov. 8, 2016, both ofwhich are incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the present invention relate to the field of mountingsystems and, in particular, to a system and method for mounting anoptical element to a printed circuit board (PCB).

BACKGROUND

In prosthodontic procedures designed to implant a dental prosthesis inthe oral cavity, the dental site at which the prosthesis is to beimplanted may be measured accurately and studied carefully, so that aprosthesis such as a crown, denture or bridge, for example, can beproperly designed and dimensioned to fit in place. A good fit, forexample, enables mechanical stresses to be properly transmitted betweenthe prosthesis and the jaw and minimizes infection of the gums via theinterface between the prosthesis and the dental site.

Some procedures call for removable prosthetics to be fabricated toreplace one or more missing teeth, such as a partial or full denture, inwhich case the surface contours of the areas where the teeth are missingmay be reproduced accurately so that the resulting prosthetic fits overthe edentulous region with even pressure on the soft tissues.

In some practices, the dental site is prepared by a dental practitioner,and a positive physical model of the dental site is constructed.Alternatively, the dental site may be scanned to providethree-dimensional (3D) data of the dental site. In either case, thevirtual or real model of the dental site may be sent to a dental labthat manufactures the prosthesis based on the model. However, if themodel is deficient or undefined in certain areas, or if the preparationwas not optimally configured for receiving the prosthesis, the design ofthe prosthesis may be less than optimal. For example, if the insertionpath implied by the preparation for a closely-fitting coping wouldresult in the prosthesis colliding with adjacent teeth, the copinggeometry may be altered to avoid the collision. Further, if the area ofthe preparation containing a finish line lacks definition, it may not bepossible to properly determine the finish line and thus the lower edgeof the coping may not be properly designed. Indeed, in somecircumstances, the model is rejected and the dental practitioner thenre-scans the dental site, or reworks the preparation, so that a suitableprosthesis may be produced.

In orthodontic procedures, it can be important to provide a model of oneor both jaws. Where such orthodontic procedures are designed virtually,a virtual model of the oral cavity is also beneficial. Such a virtualmodel may be obtained by scanning the oral cavity directly, or byproducing a physical model of the dentition, and then scanning the modelwith a suitable scanner.

Thus, in both prosthodontic and orthodontic procedures, obtaining a 3Dmodel of a dental site in the oral cavity may be an initial procedurethat is performed. When the 3D model is a virtual model, the morecomplete and accurate the scans of the dental site are, the higher thequality of the virtual model, and thus the greater the ability to designan optimal prosthesis or orthodontic treatment appliance.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings.

FIG. 1 illustrates a functional block diagram of an optical deviceaccording to one embodiment.

FIG. 2 illustrates an exploded perspective view of an optical systemaccording to one embodiment.

FIG. 3 illustrates a perspective view of a mounting system according toone embodiment.

FIG. 4A illustrates a side view of the mounting system of FIG. 3 in athermally neutral configuration.

FIG. 4B illustrates a top view of the mounting system of FIG. 3 in thethermally neutral configuration.

FIG. 5 illustrates a side view of the mounting system of FIG. 3 in athermally expansive configuration.

FIG. 6A illustrates a top view of an embodiment of a mounting systemincluding two flexures according to one embodiment.

FIG. 6B illustrates a top view of an embodiment of a mounting systemincluding three flexures according to one embodiment.

FIG. 6C illustrates a top view of an embodiment of a mounting systemincluding six flexures according to one embodiment.

FIG. 6D illustrates a top view of an embodiment of a mounting systemincluding eight flexures according to one embodiment.

FIG. 7 is a flow chart showing a method of mounting an optical element.

DETAILED DESCRIPTION

A mounting system is described herein including a base and a number offlexures attached to the base. The base may define a base planeperpendicular to a z-axis and the flexures may be pieces of materialthat protrude from the base in the direction of the z-axis and that aresubstantially flat in a direction of a corresponding y-axis radiatingfrom the z-axis.

A mounted element may be mounted to the base by attaching the flexuresto the mounted element. The flexures may be arranged such that thermalexpansion or contraction of the mounted element and/or the base bendsthe flexures outwards or inwards, e.g., in the direction of acorresponding y-axis, without bending the flexures in any otherdirection, e.g., in a direction perpendicular to the y-axis and thez-axis. Thus, the flexures allow for thermal expansion or contraction ofthe mounted element with minimal stress on components of the mountingsystem, yet prevent translational or rotational movement of the mountedelement with respect to the base.

FIG. 1 illustrates a functional block diagram of an optical device 22according to one embodiment. The optical device 22 may be a scanner,such as an intraoral scanner. The optical device 22 includes a lightsource to generate light, such as a semiconductor laser 28 that emits alaser light (represented by the arrow 30). The light passes through apolarizer 32 which gives rise to a certain polarization of the lightpassing through polarizer 32. The light then enters into an opticexpander 34 which improves the numerical aperture of the light beam 30.The light then passes through a module 38 (e.g., a grating or amicrolens array) that splits the parent beam 30 into multiple incidentlight beams 36, represented in FIG. 1 by a single line for ease ofillustration. For example, the module 38 may split the parent beam 30into a two-dimensional array of light beams.

The optical device 22 further includes a beam splitter 40 that allowstransfer of light from the laser source through the downstream optics,but redirects light travelling in the opposite direction. Thus, the beamsplitter 40 may transmit a two-dimensional array of light beams from themodule 38 to a target (via the downstream optics), but redirect areflected two-dimensional array of light beams from the target to adetector (as described below). In other embodiments, rather than a beamsplitter, other optical components with a similar function may also beused, e.g. partially transparent mirror having a small central aperture.The aperture in the mirror improves the measurement accuracy of theapparatus.

The optical device 22 further includes confocal optics 42 operating in atelecentric mode, relay optics 44, and an endoscope 46. In oneembodiment, telecentric confocal optics avoid distance-introducedmagnification changes and maintain the same magnification of the imageover a wide range of distances in the Z direction (the Z direction beingthe direction of beam propagation, also referred to as the Z axis orlens axis). The relay optics 44 allow maintenance of a certain numericalaperture of the beam's propagation.

The endoscope 46 typically includes a rigid, light-transmitting medium.The rigid, light-transmitting medium may be a hollow object definingwithin it a light transmission path or an object made of a lighttransmitting material (e.g., a glass body or tube). At its end, theendoscope typically includes a mirror of the kind ensuring a totalinternal reflection. The mirror may direct incident light beams towardsa teeth segment 26 that is being scanned. The endoscope 46 thus emitsmultiple incident light beams 48 impinging on to the surface of theteeth segment 26.

The incident light beams 48 form an array of light beams arranged in anX-Y plane propagating along the Z-axis. If the surface on which theincident light beams hit is an uneven surface, illuminated spots 52 aredisplaced from one another along the Z-axis, at different (Xi, Yi)locations. Thus, while a spot at one location may be in focus of theoptical element 42, spots at other locations may be out-of-focus.Therefore, the light intensity of the returned light beams (see below)of the focused spots will be at its peak, while the light intensity atother spots will be off peak. Thus, for each illuminated spot, multiplemeasurements of light intensity are made at different positions alongthe Z-axis. For each of such (Xi, Yi) location, typically the derivativeof the intensity over distance (Z) will be made, the Z_(i) yieldingmaximum derivative, Z₀, will be the in-focus distance. As pointed outabove, where, as a result of use of the partially transparent mirror 40,the incident light forms a light disk on the surface when out of focusand a complete light spot only when in focus, the distance derivativewill be larger when approaching in-focus position thus increasingaccuracy of the measurement.

The light scattered from each of the light spots includes a beamtravelling initially in the Z-axis along the opposite direction of theoptical path traveled by the incident light beams. Each returned lightbeam 54 corresponds to one of the incident light beams 36. Given theunsymmetrical properties of the beam splitter 40, the returned lightbeams are reflected in the direction of the detection optics 60. Thedetection optics 60 include a polarizer 62 that has a plane of preferredpolarization oriented normal to the plane polarization of polarizer 32.The returned polarized light beam 54 pass through an imaging optic 64,typically one or more lenses, and then through a matrix 66 including anarray of pinholes. A detector 68, such as a CCD (charge-coupled device)camera, has a matrix of sensing elements each representing a pixel ofthe image and each one corresponding to one pinhole in the array 66.Thus, the detector 68 may include a two-dimensional array of sensors,where each sensor determines an intensity of light impinging on thesensor.

The detector 68 is connected to the image-capturing module 80 ofprocessor unit 24. Thus, each light intensity measured in each of thesensing elements of the detector 68 is received and analyzed by aprocessor 24.

The optical device 22 further includes a control module 70 connected toa controlling operation of both the semiconductor laser 28 and anactuator 72. The actuator 72 is linked to the telecentric confocaloptics 42 to change the relative location of the focal plane of theconfocal optics 42 along the Z-axis. In a single sequence of operation,the control unit 70 induces the actuator 72 to displace the confocaloptics 42 to change the focal plane location and then, after receipt ofa feedback that the location has changed, the control module 70 willinduce the laser 28 to generate a light pulse. At the same time, thecontrol module 70 will synchronize the image capturing module 80 to grabdata representative of the light intensity from each of the sensingelements of the detector 68. Then, in subsequent sequences the focalplane will change in the same manner and the data capturing willcontinue over a wide focal range.

The image capturing device 80 is connected to processing software 82which then determines the relative intensity in each pixel over theentire range of focal planes of optics 42, 44. As explained above, oncea certain light spot is in focus, the measured intensity will bemaximal. Thus, by determining the Z_(i), corresponding to the maximallight intensity or by determining the maximum displacement derivative ofthe light intensity, for each pixel, the relative position of each lightspot along the Z-axis can be determined. Thus, data representative ofthe three-dimensional pattern of a surface in the teeth segment can beobtained. This three-dimensional representation may be displayed on adisplay 84 and manipulated for viewing, e.g. viewing from differentangles, zooming-in or out, by a user control module 86 (e.g., a computerkeyboard, touchpad, mouse, etc.). In addition, the data representativeof the surface topology may be transmitted through an appropriate dataport, e.g. a modem 88, through any communication network (e.g., a localarea network (LAN), wide area network (WAN), public network such as theInternet, etc.) to a recipient.

In embodiments, one or more of the optical elements (e.g., the polarizer32, optic expander 34, microlens array 38, beam splitter 40, confocaloptics 42, detection optics 60, etc.) may be mounted to a base using anarrangement of flexures as described herein below in greater detail. Theflexures may secure the optical elements in a manner that allows forthermal expansion or contraction of the optical element and/or base withminimal stress on components of the mounting system, yet preventstranslational or rotational movement of the mounted element with respectto the base. Thus, proper alignment of the optical components may bemaintained throughout temperature shifts.

FIG. 2 illustrates an exploded perspective view of an optical system 100according to one embodiment. The optical system 100 may be included in ascanner, such as an intraoral scanner, which may have additionalcomponents such as those described above with respect to FIG. 1. Theoptical system 100 includes a detector 110 that determines one or moreintensities of light impinging on one or more locations of the detector110. The detector 110 may include a two-dimensional array of sensors,wherein each sensor detects the intensity of light impinging on thesensor. In one embodiment, the detector 110 includes a CCD(charge-coupled device) camera.

The optical system 100 includes an optical element 120 that redirectslight towards the detector 120. The optical element 120 allows lightfrom a light source (indicated by arrow 191) to pass through the opticalelement 120 towards a target (indicated by arrow 192), but redirectslight reflected from target (indicated by arrow 193) towards thedetector 110 along a detection axis (indicated by arrow 194). Theoptical element 120 may include, for example, a beam splitter. Inanother embodiment, the optical element 120 may include a partiallytransparent mirror. The optical element may include, for example, glassor plastic or any transparent or reflective material.

The optical element 120 may be enclosed by or housed within a housing122 (shown partially cutaway in FIG. 2). In one embodiment, the housing122 is metal, e.g. aluminum. The optical element 120 may be coupled tothe housing 122 by one or more studs 124. The studs 124 may include ahead 125 that attaches to a bottom of the optical element 120 and a root126 that attaches to the housing 122.

The detector 110 may be mounted to a base 112, such as a printed circuitboard (PCB) composed of FR-4, FR-2, BT-Epoxy, Cyanate Ester, Polyimide,Polytetrafluoroethylene (PTFE), or any other material. The base 112 mayinclude conductive traces coupled to a processing device for receivingthe intensity data generated by the detector 110. The base 112 defines abase plane substantially perpendicular to the detection axis.

The optical system 100 includes a number of flexures 130A-130D forcoupling the optical element 120 to the detector 110. Whereas FIG. 2shows the optical system 100 with four flexures 130A-130D, the opticalsystem 100 may include more or fewer flexures. For example, in oneembodiment, the optical system 100 includes two flexures which may bedisposed on opposite sides of the detector 110. In another embodiment,the optical system 100 includes three or more flexures. In oneembodiment, the optical system 100 includes eight flexures.

Each of the flexures 130A-130D may be a substantially flat piece ofmaterial coupled to and protruding from the base 112. For example, theflexures 130A-130D may be welded or soldered to the base 112. In oneembodiment, the flexures 130A-130D are beryllium copper. The flexures130A-130D may also be composed of other high strength flexiblematerials, such as other metals. Although the flexures 130A-130D may besubstantially flat, an attachment face 139A-139D of each of the flexures130A-130D may be textured to improve adhesion with the optical element120 or a corresponding attachment face 129A-129D of the housing 122.

As noted above, FIG. 2 is an exploded view of the optical system 100.Once constructed, the flexures 130A-130D couple the detector 110 to theoptical element 120. In one embodiment, construction of the opticalsystem 100 includes aligning the optical element 120 with the detector110 such that a center of the redirected light 194 (e.g., a center of atwo-dimensional array of beams) is redirected to a center of thedetector 110. In one embodiment, the flexures 130A-130D are coupled tothe optical element 120 by attachment to the housing 122. In oneembodiment, the flexures 130A-130D are glued to the housing 122. In oneembodiment, glue is applied to the attachment face 139A-139D of theflexure 130A-130D and the attachment face 139A-139D is glued to acorresponding attachment face 129A-1290 of the housing 122.

The flexures 130A-130D may be arranged such that thermal expansion orcontraction of the optical element 120 (or the housing 122) with respectto the detector 110 bends the flexures outwards or inwards, e.g., in adirection radiating from the detection axis, without substantiallybending the flexures in any other direction, e.g., a directionperpendicular to the radiating direction and the detection axisdirection. For example, whereas the flexures may bend outward up to amillimeter, bending in other directions may be limited to less than amicron, maintaining sub-micron accuracy of the alignment. Thus, theflexures 130A-130D allow for thermal expansion or contraction of theoptical element 120 (or the housing 122) with minimal stress oncomponents of the mounting system 200, yet prevent translational orrotational movement of the optical element 120 with respect to thedetector 110. Thermal expansion or contraction may occur due to theoptical element 120 (e.g., a beam splitter composed of glass) having afirst coefficient of thermal expansion that is different from a secondcoefficient of thermal expansion of at least one of the detector 110 orthe base 112.

FIG. 3 illustrates a perspective view of a mounting system 200 accordingto one embodiment. The mounting system 200 may include the base 112 andflexures 130A-130D of FIG. 2. Although FIG. 3 shows four flexures130A-130D, the mounting system 200 may include more or fewer flexures.As described above, a detector and an optical element may be coupledtogether using the mounting system 200. However, the mounting system 200may be used to couple other components.

The base 112 includes a substantially flat surface defining a base planeperpendicular to a z-axis 132. The flexures 130A-130D are substantiallyflat pieces of material protruding from the base in the direction of thez-axis 132. The flexures 130A-130D are respectively associated withxy-axes 134A-134D perpendicular to the z-axis, wherein each y-axis isperpendicular to and radiating from the z-axis and wherein each x-axisis perpendicular to both the z-axis and the corresponding x-axis. Thexy-axes 134A-134D may be defined by an attachment face spanning acorresponding xz-plane, referred to as a flexure plane, which isperpendicular to the base plane and, thus, parallel to the z-axis. Theflexure planes, in turn, define flexure lines 136A-1360 normal to theflexure plane (e.g., along the y-axis). The flexure lines 136A-136D meetat an intersection point 138. The flexures 130A-130D may be flexiblealong a respective flexure line 136A-1360 and rigid perpendicular to therespective flexure line 136A-1360.

With respect to FIG. 3, the flexures 130A-130D include a first flexure130A defining a first flexure line 136A, a second flexure 130B defininga second flexure line 136A collinear with the first flexure line 136A, athird flexure 130C defining a third flexure line 136C perpendicular tothe first flexure line 136A, and a fourth flexure 130D defining a fourthflexure line 136C collinear with the third flexure line 136C. Theflexure lines 136A-1360 meet at the intersection point 138.

As discussed above, the optical element 120 may be aligned with thedetector 110 such that a center of the redirected light 194 (e.g., acenter of a two-dimensional array of beams) is redirected to a center ofthe detector 110. The detector 110 may be mounted on the base such thatthe flexures surround, but do not contact the detector 110. Theintersection point 138 provides a stationary point of the system suchthat the center of the redirected light 194 is redirected to the centerof the detector regardless of thermal expansion or contraction of thecomponents of the system, as the flexures 130A-130D are rigid along arespective first axis and flexible along a respective second axis, therespective first axis and the respective second axis being generallyparallel to a face of the detector. Moreover, the optical element 120may maintain a fixed position, such that each pixel of the detectorremain aligned with respective source beams to sub-micron accuracy andstability over a wide range of thermal conditions.

In one embodiment, a mounted element (such as the optical element 120and housing 122 of FIG. 2) includes substantially flat attachment faces(such as the attachment faces 129A-1290 of the housing 122 of FIG. 2)that respectively define face planes, each of the three or more faceplanes being parallel to one of the flexure planes. Mounting the mountedelement may include aligning the mounted element to the detector andattaching the flexures 130A-130D to the mounted element, e.g., by gluingattachment faces of the flexures 130A-130D to attachment faces of themounted element. The mounted element may be mounted to the base 112 suchthat a center of the mounted element is aligned with the intersectionpoint 138.

Each flexure 130A-130D may have a height in a first direction (e.g.,along the z-axis), a thickness in a second direction (e.g., along they-axis), and a width in a third direction (e.g., along the x-axis.). Inone embodiment, the thickness is substantially smaller than the heightand the width. For example, in one embodiment, the thickness is lessthan one-tenth the height and the width. In one embodiment, thethickness is less than one millimeter and the height and width are atleast ten millimeters. In one embodiment, the width is greater than theheight. For example, the width may be at least 20% greater than theheight. In another embodiment, the width and height are approximatelyequal.

In one embodiment, the flexures 130A-130D are bent at approximately a90-degree angle at one end that attaches to the base 112. This mayprovide a greater surface area to attach the flexures 130A-130D to thebase 112. In one embodiment, the bent end of the flexures 130A-130D isdivided into multiple sections (e.g., three sections), with a one ormore sections being bent 90-degrees in a first direction and one or moreother sections being bent at 90 degrees in an opposite direction.

FIG. 4A illustrates a side view of the mounting system 200 of FIG. 3 ina thermally neutral configuration. FIG. 4B illustrates a top view of themounting system 200 of FIG. 3 in the thermally neutral configuration. Inthe thermally neutral configuration of FIGS. 4A-4B, the flexures130A-130D are coupled to a mounted element 300 and unbent. If themounted element 300 experiences thermal expansion or contraction withrespect to the mounting system 200 and/or base due to a difference inthe coefficients of thermal expansion of the materials of the mountedelement 300, the mounting system 200 and/or the base, the mountingsystem may be in a thermally expansive or thermally contractedconfiguration.

FIG. 5 illustrates a side view of the mounting system 200 of FIG. 3 in athermally expansive configuration. In the thermally expansiveconfiguration, the flexures 130A-130D remain coupled to the mountedelement 300, but are bent in an outward direction (along the respectivey-axes defined by the flexures). Thus, the flexures 130A-130D act asleaf springs, each flexure providing flexibility in one direction (e.g.along the y-axis) and stiffness in an orthogonal direction (e.g., alongthe x-axis). As shown in FIG. 5, only a portion of the flexures130A-130D may bend. In particular, a portion attached to the mountedelement 300 and a portion proximal to the base 112 may maintain a fixedposition.

Although the flexures 130A-130D bend outward, allowing the mountedelement 300 to thermally expand, the flexures 130A-130D do not bend ordeform in other directions (e.g., along the x-axis), maintainingalignment of the mounted element 300 with respect to the base.Additionally, each flexure 130A-130D may bend by an approximatelyequivalent amount and thus exert approximately the same force on themounted element 300. Thus, the forces equalize, resulting in the mountedelement 300 maintaining a fixed position relative to the base 112. Inparticular, the flexures 130A-130D may maintain an alignment of a centerof an optical element (such as a beam splitter) to a center of adetector attached to the base 112. Moreover, there is very little,insignificant, movement along the Z-axis.

In an optical system with materials having different thermalcoefficients of expansion, the bending of the flexures in one directionreduces stress on the components that would otherwise be present.However, the lack of bending or deformation of the flexures in otherdirections maintains the alignment of the system and, thus, providesstability to the system.

As shown, in embodiments, the mounting system 200 and its optics are notdirectly affixed to the detector. Instead, the mounting system 200 isaffixed to the base (e.g., PCB), which in turn is affixed to thedetector. This lack of direct connection between the mounting system andthe detector in theory could cause the optics to fall out of alignmentwith respect to the detector. However, an unexpected result of the useof the flexures described in embodiments is that sub-micron alignment ismaintained between the detector and optics in the mounting system 200even without a direct attachment between the detector and the mountingsystem. In one embodiment, such alignment is facilitated by using a basethat has a coefficient of thermal expansion that is approximately equalto a coefficient of thermal expansion of the detector.

The use of the flexures 130A-130D to attach the optical element 120 (orhousing 122) to the base 112 rather than directly to the detectorenables the detector to have a minimal package size. Thus, embodimentsdescribed herein facilitate miniaturization of devices for which preciseoptical alignment between components with possibly differentcoefficients of thermal expansion is important.

As noted above, although FIG. 3 shows four flexures 130A-130D, themounting system 200 may include more or fewer flexures. FIGS. 6A-6D showembodiments of mounting systems having various numbers of flexures.

FIG. 6A illustrates a top view of an embodiment of a mounting system 610including two flexures 612A-612B according to one embodiment. Theflexures 612A-612B are disposed on opposite sides of a mounted element615. Thus, in one embodiment, a mounting system may include a basehaving a substantially flat surface defining a base plane and two ormore substantially flat flexures protruding from the base, the two ormore substantially flat flexures respectively defining two or moreflexure planes approximately perpendicular to the base plane, the two ormore flexure planes respectively defining two or more flexure linesperpendicular to the flexure planes, wherein each of the two or moresubstantially flat flexures is flexible along a respective flexure lineof the two or more flexure lines and is rigid perpendicular to therespective flexure line, and wherein the two or more flexure lines meetat an intersection point.

Similarly, an optical system may include a detector to determine one ormore intensities of light impinging on one or more locations of thedetector, an optical element to redirect light towards the detectoralong a detection axis, and two or more substantially flat flexuresindirectly coupling the optical element to the detector, the two or moresubstantially flat flexures respectively defining two or more flexureplanes parallel to the detection axis, each of the two or moresubstantially flat flexures being rigid along a respective first axisand flexible along a respective second axis, the respective first axisand the respective second axis being generally parallel to a face of thedetector.

FIG. 6B illustrates a top view of an embodiment of a mounting system 620including three flexures 622A-622C according to one embodiment. Theflexures 622A-622C are disposed around a mounted element 625 such thatflexure lines 624A-6240 defined by the flexures 622A-622C meet at anintersection point 628 and form 120-degree angles with each other. Thus,the flexures 622A-622C are equally spaced about the mounted element 625.In other embodiments, the flexures 622A-622C are not equally spacedabout the mounted element 625.

FIG. 6C illustrates a top view of an embodiment of a mounting system 630including six flexures 632A-632G according to one embodiment. Althoughthe six flexures 632A-632F are shown disposed around the mounted element635 with equal spacing, in other embodiments, the flexures 632A-632F maynot be equally spaced about the mounted element 635. FIG. 6D illustratesa top view of an embodiment of a mounting system 640 including eightflexures 642A-642H according to one embodiment. Although the eightflexures 642A-642H are shown disposed around the mounted element 645with equal spacing, in other embodiments, the flexures 642A-642H may notbe equally spaced about the mounted element 645.

FIG. 7 is a flow chart showing a method 700 of mounting an opticalelement. The method 700 begins in block 710 with attaching three or moreflexures to a base. The base may include, for example, a printed circuitboard (PCB). The flexures may be attached at a free end to the base suchthat the flexures protrude from the base. In one embodiment, theflexures are attached by welding or soldering the flexures to base. Inanother embodiment, the flexures may be glued to the base or otherwiseattached.

In block 720, a detector is mounted to the base. The detector may bemounted to the base such that the detector contacts conductive tracingsof the base to communicate data from the detector to a processor orother component. In one embodiment, the detector is glued or soldered tothe base. The detector may be mounted to the base such that it issurrounded by, but does not contact, the flexures.

In block 730, an optical element is aligned with respect to thedetector. The optical element may include, for example, a beam splitter.The optical element may be align in six degrees of freedom, e.g., threetranslational directions along a set of three perpendicular axes andthree rotational directional about the axes. The optical element may bealigned with a sub-micron accuracy.

In block 740, the three or more flexures are attached to the opticalelement. In one embodiment, the three or more flexures are glued to theoptical element (or a housing surrounding the optical element). In oneembodiment, glue is applied to the flexures and the flexures are pressedagainst a portion of the optical element or the housing. In oneembodiment, the flexures are glued to the optical element or the housingprior to alignment and the glue is cured after alignment has beenperformed. In another embodiment, the flexures are attached to theoptical element in other ways.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Many other embodiments will beapparent upon reading and understanding the above description. Althoughembodiments of the present invention have been described with referenceto specific example embodiments, it will be recognized that theinvention is not limited to the embodiments described, but can bepracticed with modification and alteration within the spirit and scopeof the appended claims. Accordingly, the specification and drawings areto be regarded in an illustrative sense rather than a restrictive sense.The scope of the invention should, therefore, be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

What is claimed is:
 1. A scanner comprising: a base; a detector mountedto the base; an optical element to redirect light reflected off of atarget towards the detector along a detection axis in a first direction;and three or more flexures that couple the optical element to the base,wherein thermal expansion or contraction of the optical element withrespect to at least one of the detector or the base bends each flexureof the three or more flexures in a respective second direction withoutbending the flexure in a respective third direction approximatelyperpendicular to the first direction and the respective seconddirection, wherein the three or more flexures maintain an alignment ofthe optical element to the detector with changes in temperature.
 2. Thescanner of claim 1, wherein the optical element is a beam splitter. 3.The scanner of claim 1, further comprising: a light source to generatethe light.
 4. The scanner of claim 3, further comprising: a microlensarray to split the light into an array of light beams; wherein theoptical element is to transmit the array of light beams towards thetarget and redirect a reflected array of light beams from the targettowards the detector along the detection axis in the first direction;and wherein the detector comprises one or more sensors, wherein eachsensor of the one or more sensors is to determine an intensity of lightimpinging on the sensor.
 5. The scanner of claim 4, wherein the three ormore flexures further maintain an alignment of the microlens array tothe detector with changes in temperature.
 6. The scanner of claim 1,wherein the optical element has a first coefficient of thermal expansionthat is different from a second coefficient of thermal expansion of atleast one of the detector or the base.
 7. The scanner of claim 1,wherein each flexure has a height in the first direction, a thickness inthe respective second direction, and a width in the respective thirddirection, wherein the thickness is less than one-tenth the height andthe width.
 8. The scanner of claim 1, wherein the three or more flexuresmaintain an alignment of the optical element to the detector to asub-micron level of accuracy and stability.
 9. The scanner of claim 1,wherein the base comprises a printed circuit board (PCB) having a firstcoefficient of thermal expansion that is approximately equal to a secondcoefficient of thermal expansion of the detector, the optical elementcomprises an optical beam-splitting element in a housing, and the threeor more flexures attach the PCB to the housing.
 10. The scanner of claim9, wherein the housing comprises metal.
 11. The scanner of claim 1,wherein the base has a substantially flat surface defining a base plane,the three or more flexures respectively define three or more flexureplanes approximately perpendicular to the base plane, the three or moreflexure planes respectively defining three or more flexure linesperpendicular to the flexure planes, wherein each of the three or moreflexures is flexible along a respective flexure line of the three ormore flexure lines and is rigid perpendicular to the respective flexureline, wherein the three or more flexure lines meet at an intersectionpoint, and wherein the intersection point is maintained with the changesin temperature.
 12. The scanner of claim 1, wherein the three or moreflexures comprise a first flexure defining a first flexure line, asecond flexure defining a second flexure line collinear with the firstflexure line, a third flexure defining a third flexure lineperpendicular to the first flexure line, and a fourth flexure defining afour flexure line collinear with the third flexure line.
 13. The scannerof claim 1, wherein the three or more flexures comprise berylliumcopper.
 14. The scanner of claim 1, wherein the three or more flexuressurround, but do not contact, the detector.
 15. A method of mounting anoptical element, comprising: attaching three or more flexures to a basehaving a substantially flat surface defining a base plane, wherein thethree or more flexures are mounted to the base such that: the three ormore flexures protrude from the base; the three or more flexures are tosurround a detector attached to the base; and the three or more flexuresare attached to the base such that the three or more flexuresrespectively define three or more flexure planes approximatelyperpendicular to the base plane, the three or more flexure planesrespectively defining three or more flexure lines perpendicular to theflexure planes, wherein each of the three or more flexures is flexiblealong a respective flexure line of the three or more flexure lines andis rigid perpendicular to the respective flexure line, wherein the threeor more flexure lines meet at an intersection point; aligning theoptical element with the detector such that a center of the opticalelement aligns with a center of the detector; and attaching the three ormore flexures to the optical element while the optical element isaligned with the detector, wherein the intersection point is maintainedwith changes in temperature.
 16. The method of claim 15, whereinattaching the three or more flexures to the base comprises welding orsoldering the three or more flexures to the base.
 17. The method ofclaim 15, wherein the optical element is housed within a housing, andwherein attaching the three or more flexures to the optical elementcomprises gluing the three or more flexures to the housing.
 18. Themethod of claim 17, wherein the housing comprises three or moresubstantially flat attachment faces that respectively define three ormore face planes, wherein each of the three or more face planes isparallel to one of the three or more flexure planes, and wherein gluingthe three or more flexures to the housing comprises applying glue toeach of the three or more substantially flat attachment faces.
 19. Themethod of claim 15, further comprising: mounting the detector to thebase after attaching the three or more flexures to the base, wherein thethree or more flexures do not contact the detector.
 20. The method ofclaim 15, wherein the optical element, the base, the three or moreflexures and the detector are components of a scanner.